feat(workshops): VHS Worms 2026 workshops with improved styling

- Add 4 VHS Worms 2026 courses (Feb-Jun 2026)
- Use markdown-native Material grid cards design
- Fix page rendering (remove workshops blog plugin)
- Add equal height cards via flexbox CSS
- Remove awkward checkmark pseudo-elements
- Make page full-width layout (hide navigation sidebar)

Courses: KI-Chatbots (Feb 21), KI-Einsatz im Beruf (Mar 14),
Videos mit KI (Apr 18), Programmieren mit KI (Jun 20)

overrides/assets/css/custom.scss

@@ -31,7 +31,8 @@
 @import "modules/slideshow";
 @import "modules/blog";
 @import "modules/tooltips"; // Fix for issue #70: Tooltip width improvements
+@import "modules/workshops"; // VHS Worms workshop cards styling
 
 //Responsive Design
 @import "responsive/medium";
-@import "responsive/mobile";
+@import "responsive/mobile";